Neoplasia Flashcards
What is a tumour?
A swelling that can be benign or malignant.
May even be inflammatory, or a foreign body.
What is a neoplasm?
A new growth that is not in response to a stimulus.
Can be benign, premalignant, or malignant.
Define “malignant”
A tumour with metastatic potential, that goes beyond the basement membrane.
Define “metaplasia”
Reversible change from one mature cell type to another mature cell type.
Represents a change in signals delivered to stem cells causing them to differentiate down a different line.
Signals may be cytokines, growth factors, etc.
Metaplastic tissue is….
….an at risk site for the development of cancer
Define “hyperplasia”
The enlargement of cells
What is dysplasia?
Disordered growth
Abnormal cells
No invasion
Often graded between most normal and closest to cancer
Factors that cause cancer
Genes Smoking Alcohol UV radiation Other radiation Drugs Infections Obesity
What are Weinberg’s Hallmarks?
Increase growth signals Remove growth suppression Avoid apoptosis Achieve immortality Become invasive Make your own blood supply (angiogenesis) Less of DNA spell checks Avoid the immune system
What is the double hit hypothesis?
One working gene is enough.
Two faulty copies have a functional problem.
Those who have inherited one faulty copy are at higher risk
What are initiators?
Causing long lasting genetic damage.
Not sufficient to cause cancer.
Most be followed by a promoter to require initiators to have caused damage.
What is a promoter?
Require initiators to have caused damage.
Time period can vary after initiation.
Chemical carcinogens is all seem to cause what?
DNA damage. Seem to cause specific and recurrent genetic alteration based on the chemical involved.
Aflatoxin = p53
Polycyclic aromatic hydrocarbons are…
A potent carcinogen.
Paint it on skin = cancer
Can be present in animal fat
Aflatoxins cause
Liver cancers.
They are from fungus and common in china.
Associated with p53 mutations.
What are the three categories of growth receptors?
Receptors with intrinsic tyrosine kinase activity
7 transmembrane G protein-coupled receptors
Receptors without intrinsic tyrosine kinase activity
MAPK/ERK Pathway
EGFR overexpression
RAS mutation
BRAF mutation
C-KIT mutation leads to…
Gastrointestinal stromab tumours
BRAF leads to what cancers?
Melanomas
Myc is
One of the last points in the sequence.
Myc is a nuclear transcription factor that promotes growth.
Common in lymphoma, neuroblastoma, small cell carcinoma of the lung.
PI3K
Most commonly mutated kinase in cancer
Tumour suppressor genes
Proteins that inhibit the cell cycles, often prefixed by a little “p”
For example p53
What does p53 do?
Senses DNA abnormalities at G1 and pauses the cells cycle. Increases levels of p21 which is a CDK inhibitor.
If DNA repaired, p53 restarts the cell cycle, if not it initiates apoptosis
PTEN
Increases transcription of p27
P27 blocks CDKs and cell cycle progression.
Inhibits PI3K/AKT pathway.
Without PTEN, p27 cells can proliferate in an uncontrollable fashion
